I am sure that if downloading the brain information into a hard drive will be possible, the rich majority will try to keep it for themselves. They will not want to have too many immortals out there.
That could be why you have never heard of it

Immortal might be a bit of a misnomer... The person could still die, like always... Just not death by old age... A bullet, or heart-attack could still be lethal
Though, I suppose if they did a nightly backup of their brain, they could have an emergency backup plan in case of death...
Fairly certain I saw a movie with this... the had these little dots under their eye-lids to show how many times they had been cloned already...
https://en.wikipedia.org/wiki/The_6th_Day